New rice varieties/lines developed

Promising new rice varieties are being developed and scrutinized at the LSU Rice Research Station in Crowley, La. Catahoula, an early semi-dwarf long-grain “has very good yield potential,” said Steve Linscombe, LSU AgCenter rice breeder and station manager, at the recent field day in Crowley. “In fact, when averaged over a number of years, it appears to have an advantage over both Cocodrie and Cheniere.”

As for disease susceptibility, “it’s more similar to Cheniere. It is susceptible to sheath blight but not as much as the most susceptible long grains. It has very good blast resistance. One of the parents of Catahoula is the older Arkansas variety, Drew.

“Drew is no longer grown (on major acreage), but it did have very good blast disease resistance. We were fortunate to be able to incorporate that into this new variety.”

Another variety growers will be hearing about is a new Clearfield, CL151. “It’s been in development for a few years and is being widely grown for seed increase throughout the Gulf South. Unless something unforeseen happens, it should be readily available in 2009.”

CL151 has been “pretty consistent” in showing a distinct yield advantage over the current Clearfield varieties such as CL161, CL131 and CL171. “We’re anxious to get the seed out. Next year, we believe it will be grown on wide acreage.”

Part of a multi-state testing effort, Linscombe and colleagues are also checking a number of lines from cooperating breeding programs.

“Bowman is a new, long grain rice released by Dwight Kanter in Stoneville, Miss. Compared to some of the Louisiana lines, it has much wider leaves — a somewhat more predominant flag leaf. It looks to have very good yield potential, very good blast resistance.”

Bowman is also a Rexmont cooking type of rice. “That means it has a higher level of amylose than our conventional long grains. This particular processing type is preferred by the canning industry, for example. Campbell’s uses a lot of these types of varieties in soups.”

Linscombe also pointed out several experimental lines from Arkansas. “AR-1182 is a line from Karen Moldenhauer’s program. It’s a more typical Wells-looking plant type that has shown very good yield potential in our trials.

“AR-1142 is a very early semi-dwarf from James Gibbons. One of its parents is a Brazilian variety, IRGA417. We’re anxious to see how it performs because it looks pretty good up to now.”

For the first time, the station is also growing one of the Bayer rice hybrids. “Bayer is actively involved in hybrids for the Gulf South region. Arize 1003 will be a bit late for us — about 10 days later than Cocodrie. But we’re anxious to see how it does under our growing conditions.”

LSU AgCenter breeders are continuously trying to develop new varieties, “both conventional and with the Clearfield technology. Three of the Clearfield long grains showing promise: LA-0802002, LA-0802008, and LA-0802051, the tallest of the three. All are very early and have looked very good in the testing program. We’ll probably be making a decision to go with a larger seed increase on one of the lines after we see this year’s data.

“We’re also trying to develop a Clearfield medium grain. Last year, we told you about a line, 005, and thought it would be the first Clearfield medium grain. We took it down to Puerto Rico for a seed increase last winter.”

To develop a Clearfield medium grain, researchers must cross a Clearfield long grain — since that’s where the desired herbicide resistance gene is — with a conventional medium grain.

“When going through the segregating generations, it’s easy to screen for the Clearfield resistance. We simply spray (the rice) with Newpath herbicide. That weeds out the segregates that don’t have the (desired) gene. It’s pretty easy to select for a grain type and agronomic characteristics.”

However, one thing that can “confound” the program is crossing two distinct cereal chemistries. Long grains have high amylose/intermediate gel temperatures while medium grains have low amylose/low gel temperatures.

“We thought we had the 005 line stable for the medium grain cooking characteristics. But when we started looking at additional samples, there were some concerns. Based on that, we said, ‘We’ll halt this line because there are a couple more that are even better.’

“The 065 and 068 are both very nice medium grains with the Clearfield gene and appear to have the stability for the cook type. They’ve performed very well in our yield test studies. We’ll study the data and make a decision on expediting a seed increase and probably take headrows of one of the lines to Puerto Rico.”

In recent years, Xueyan Sha, a rice breeder working with Linscombe, has focused on conventional long grains and, especially, aromatics.

This is the first year for the seed production of Neptune, the latest medium grain release from LSU. “Compared to Jupiter — which was released about three years ago — Neptune has similar yield potential, if not higher,” said Sha. “But Neptune has a bigger grain size and better milling yield. Disease-wise, it has much improved resistance to blast.”

Agronomically, Neptune is an inch or two shorter than Bengal and Jupiter. Neptune can head out two or three days later but actually reaches harvest maturity earlier than Bengal and Jupiter. It also has very good and consistent ratoon potential, especially for a medium grain. Neptune seed should be readily available in 2009.

Developing aromatic rice varieties takes a while, said Sha. “We’re not only looking for good yields, milling yields and a disease resistance (package), we’re also looking for specialty characteristics like aroma and cooking quality. That’s what makes Jasmine rice and it takes extra time.”

With that in mind, “LA-2125 has excellent yield potential, even when compared to conventional varieties like Cypress. It also has a very good and stable milling yield. In our trials, it consistently reaches the low 60s in head rice. Most importantly, it has a Jasmine-type cooking quality.”

The line looks similar to Wells with plant height, maturity and straw strength. It also has “a pretty good disease package. It is slightly susceptible to sheath blight but highly resistant to blast. It also has smooth leaves and sheath and no dormancy.”